Direct Catalytic Desaturation of Lactams Enabled by Soft Enolization
作者:Ming Chen、Guangbin Dong
DOI:10.1021/jacs.7b04722
日期:2017.6.14
N-protected lactams to their conjugatedunsaturated counterparts under mildly acidic conditions. The reaction is consistently operated at room temperature and tolerates a wide range of functional groups, showing reactivity complementary to that of prior desaturation methods. Lactams with various ring sizes and substituents at different positions all reacted smoothly. The synthetic utility of this method
For the construction of the tricyclic core of manzamine A (1), the Diels-Alder reactions of some dihydropyridinones were surveyed. The N-protecting group of the dihydropyridinone played an important role in achieving a successful Diels-Alder reaction. In view of its electron-withdrawing character as well as its thermal stability, the p-toluenesulfonyl protecting group was found to be best in our synthesis. An effective method for the preparation of 3-alkyldihydropyridinones via the Michael addition to dehydroalanine derivatives has also been devised. By the utilization of a high-pressure Diels-Alder reaction of the N-tosyl-3-alkyldihydropyridinone (17) with the Danishefsky diene, a facile construction of the central pyrroloisoquinoline skeleton (21) was successfully achieved.
NAKAGAWA, MASAKO;LAI, ZIPING;TORISAWA, YASUHIRO;HINO, TOHRU, HETEROCYCLES, 31,(1990) N, C. 993-1002